*{
    margin: 0;
    padding: 0;
}
#container{
    width: 400px;
    height: 200px;
    margin:0 auto;
}
#pre:after{
    width: 30px;
    height: 50px;
    margin-left:0px;
    margin-top:75px;
    float: left;
    line-height: 50px;
    text-align: center;
    font-weight: bold;
    font-size: 40px;
    background-color: gray;
    color:white;
    content: '<';
}
#next:after{
    width: 30px;
    height: 50px;
    margin-right:0px;
    margin-top:75px;
    float: right;
    line-height: 50px;
    text-align: center;
    font-weight: bold;
    font-size: 40px;
    background-color: gray;
    color:white;
    content: '>';
}
.number{
    width: 26px;
    height: 13px;
}
.dot{
    border-radius: 50%;
    width: 13px;
    height: 13px;
    display: inline-block;
    background-color: grey;
}
.dot:hover{
    background-color: black;
}
#pre:hover,#next:hover{
    background-color: white;
    color:black;
}
#pre:hover:after
{
    width:100px;
    content: 'pre';
}
#next:hover:after{
    width:100px;
    content: 'next';
}
img{
    position: absolute;
    left:50%;
    margin-left: -50px;
    height: 100px;
    width: 100px;
    top:50px;
}
#dot{
    width: 49px;
    height: 13px;
    margin:0 auto;
    margin-top: 150px;
}
.active{
    background-color: black;
}